下面的查询中哪一个会产生笛卡尔集（）A、SELECT e.empno，e.ename， e.deptno， d.deptno，d.loc FROM emp e，dept d WHERE e.deptno=d.deptnoB、SELECT e.empno， e.ename， e.deptno， d.deptno，d.loc FROM emp e，dept dC、SELECT e.empno， e.ename， e.deptno， d.deptno，d.loc FROM emp e，dept d WHERE e.empno=101 and e.deptno=d.deptnoD、SELECT e.empno， e.ename， e.deptno， d.deptno，d.loc FROM emp e，dept d WHEREe.deptno=d.deptno and d.deptno=60
下面的查询中哪一个会产生笛卡尔集（）
- A、SELECT e.empno，e.ename， e.deptno， d.deptno，d.loc FROM emp e，dept d WHERE e.deptno=d.deptno
- B、SELECT e.empno， e.ename， e.deptno， d.deptno，d.loc FROM emp e，dept d
- C、SELECT e.empno， e.ename， e.deptno， d.deptno，d.loc FROM emp e，dept d WHERE e.empno=101 and e.deptno=d.deptno
- D、SELECT e.empno， e.ename， e.deptno， d.deptno，d.loc FROM emp e，dept d WHEREe.deptno=d.deptno and d.deptno=60
相关考题：
以下语句不正确的是( )A.select * from emp;B.select ename,hiredate,sal from emp;C.select * from emp order deptno;D.select * from where deptno=1 and sal
Which SQL statement would you use to remove a view called EMP_DEPT_VU from your schema?() A. DROP emp_dept_uv;B. DELETE emp_dept_uv;C. REMOVE emp_dept_uv;D. DROP VIEW emp_dept_uv;E. DELETE VIEW emp_dept_uv;F. REMOVE VIEW emp_dept_uv;
根据SQL标准，要查询表student中平均年龄age小于21的所在系dept及其平均年龄值，下面哪条语句适用?()A select dept,avg(age) from student where avg(age)B select dept,avg(age) from student group by dept having avg(age)C select dept,avg(age) from student having avg(age)D select dept,avg(age) from student group by dept where avg(age)
Examine the description of the EMPLOYEES table:EMP_ID NUMBER(4) NOT NULLLAST_NAME VARCHAR2(30) NOT NULLFIRST_NAME VARCHAR2(30)DEPT_ID NUMBER(2)JOB_CAT VARCHARD2(30)SALARY NUMBER(8,2)Which statement shows the maximum salary paid in each job category of each department? （）A. SELECT dept_id, job_cat, MAX(salary) FROM employees WHERE salary MAX (salary);B. SELECT dept_id, job_cat, MAX(salary) FROM employees GROUP BY dept_id,job_cat;C. SELECT dept_id, job_cat, MAX(salary) FROM employees;D. SELECT dept_id, job_cat, MAX(salary) FROM employees GROUP BY dept_id;E. SELECT dept_id, job_cat, MAX(salary) FROM employees GROUP BY dept _ id job _ cat salary;
Which of the following statements eliminates all but one of each set of duplicate rows in the DEPT column in the STAFF table?() A.SELECT UNIQUE dept FROM staffB.SELECT DISTINCT dept FROM staffC.SELECT (dept) UNIQUE FROM staffD.SELECT (dept) DISTINCT FROM staff
列出EMP表中,从事每个工种(JOB)的员工人数() A.select job from emp;B.select job,count(*) from emp;C.select distinct job,count(*) from emp;D.select job,count(*) from emp group by job;E.select job,sum(empno) from emp group by job;
限制从EMP表中只选出前5条记录的查语句为()。 A.SELECT TOP 5 * FROM EMPB.SELECT DISTINCT 5 * FROM EMPC.SELECT * FROM EMP WHERE ROWNUM6D.SELECT * FROM EMP WHERE ROWNUM=5
找出emp表中的dept表没有的dept_no 使用Exists方式实现 即改写select * from emp a where a.dept_no not in (select b.dept_no from dept b)
某企业部门关系模式Dept（部门号，部门名，负责人工号，任职时间），员工关系模式EMP（员工号，姓名，年龄，月薪资，部门号，电话，办公室）。部门和员工关系的外键分别是（ ）。查询每个部门中月薪资最高的员工号、姓名、部门名和月薪资的SQL查询语句如下：SELECT员工号，姓名，部门名，月薪资FROM EMP Y,DeptWHERE（请作答此空）AND月薪资=（SELECT Max（月薪资）FROM EMP Z WHERE（ ）A.Y．部门号=Dept.部门号B.EMP.部门号=Dept.部门号C.Y.员工号=Dept.负责人工号D.EMP.部门号=Dept.负责人工号
使用HQL查询所有部门信息，以下正确的是（）。A、from DeptB、select*from cn.jbit.demo.entity.DeptC、select Dept from cn.jbit.demo.entity.Dept dD、select d from Dept d
关于HQL的聚合函数使用，说法正确的是（）。A、select count(*) from Dept d用于统计部门个数B、select sum(e.salary) from Emp e用于汇总员工工资总额C、select max(e.hiredate) from Emp e用于找到最新入职的员工的入职时间D、select min(e.hiredate) from Emp e用于找到最早入职的员工的入职时间
查询出EMP表中1982年及以后入职的员工信息（）（注：字段hiredate为入职日期，数据类型为DATE型）A、select * from emp where hiredate='19820101';B、select * from emp where hiredate=to_char('19820101','YYYYMMDD');C、select * from emp where to_date(hiredate,'YYYYMMDD')='19820101';D、select * from emp where to_char(hiredate,'YYYYMMDD')='19820101';
Which of the following statements eliminates all but one of each set of duplicate rows in the DEPT column in the STAFF table?（）A、SELECT UNIQUE dept FROM staffB、SELECT DISTINCT dept FROM staffC、SELECT (dept) UNIQUE FROM staffD、SELECT (dept) DISTINCT FROM staff
语句SELECT * FROM dept WHERE NOT EXISTS （SELECT * FROM emp WHERE deptno=dept.deptno）执行后的结果为（）A、只显示存在于EMP表中的部门全部信息B、只显示不存在于EMP表中的部门全部信息C、未返回任何数据D、显示DEPT表中的全部信息
A number of applications issue the following SQL statement:SELECT d.deptno, e.empno, e.salary FROM department d INNER JOIN employee e ON d.deptno = e.deptnoA database administrator wishes to store this query within the database. Which of the following database objects can be used to accomplish this?（）A、AliasB、ViewC、SchemaD、Trigger
Examine the description of the EMPLOYEES table: EMP_ID NUMBER(4) NOT NULL LAST_NAME VARCHAR2(30) NOT NULL FIRST_NAME VARCHAR2(30) DEPT_ID NUMBER(2) JOB_CAT VARCHAR2(30) SALARY NUMBER(8,2) Which statement shows the department ID, minimum salary, and maximum salary paid in that department, only of the minimum salary is less then 5000 and the maximum salary is more than 15000?（）A、SELECT dept_id, MIN(salary(, MAX(salary) FROM employees WHERE MIN(salary) 5000 AND MAX (salary) 15000;B、SELECT dept_id, MIN(salary), MAX(salary) FROM employees WHERE MIN(salary) 5000 AND MAX(salary) 15000 GROUP BY dept_id;C、SELECT dept_id, MIN(salary), MAX(salary) FROM employees HAVING MIN(salary) 5000 AND MAX (salary) 15000;D、SELECT dept_id, MIN(salary), MAX(salary) FROM employees GROUP BY dept_id HAVING MIN (salary) 5000 AND MAX(salary)E、SELECT dept_id, MIN(salary), MAX(salary) FROM employees GROUP BY dept_id, salary HAVING MIN (salary) 5000 AND MAX (salary) 15000;
Examine the description of the EMPLOYEES table: EMP_ID NUMBER(4) NOT NULL LAST_NAME VARCHAR2(30) NOT NULL FIRST_NAME VARCHAR2(30) DEPT_ID NUMBER(2) Which statement produces the number of different departments that have employees with last name Smith?（）A、SELECT COUNT(*) FROM employees WHERE last_name='Smith';B、SELECT COUNT(dept_id) FROM employees WHERE last_name='Smith';C、SELECT DISTINCT(COUNT(dept_id)) FROM employees WHERE last_name='Smith';D、SELECT COUNT(DISTINCT dept_id) FROM employees WHERE last_name='Smith';E、SELECT UNIQUE(dept_id) FROM employees WHERE last_name='Smith';
You created a view called EMP_DEPT_VU that contains three columns from the EMPLOYEES and DEPARTMENTS tables: EMPLOYEE_ID, EMPLOYEE_NAME AND DEPARTMENT_NAME. The DEPARTMENT_ID column of the EMPLOYEES table is the foreign key to the primary key DEPARTMENT_ID column of the DEPARTMENTS table. You want to modify the view by adding a fourth column, MANAGER_ID of NUMBER data type from the EMPLOYEES tables. How can you accomplish this task?（）A、ALTER VIEW EMP_dept_vu (ADD manger_id NUMBER);B、MODIFY VIEW EMP_dept_vu (ADD manger_id NUMBER);C、ALTER VIEW emp_dept_vu AS SELECT employee_id, employee_name, department_name, manager_id FROM employee e, departments d WHERE e.department _ id = d.department_id;D、MODIFY VIEW emp_dept_vu AS SELECT employee_id, employee_name, department_name, manager_id FROM employees e, departments d WHERE e.department _ id = d.department_id;E、CREATE OR REPLACE VIEW emp_dept_vu AS SELECT employee_id, employee_name, department_name, manager_id FROM employees e, departments d WHERE e.department _ id = d.department_id;F、You must remove the existing view first, and then run the CREATE VIEW command with a new column list to modify a view.
查询出所有名字以’S’开始的员工（）A、select * from emp where ename in 'S%';B、select * from emp where ename='S%';C、select * from emp where ename like 'S%';D、select * from emp where ename like 'S_';
Examine the description of the EMPLOYEES table: EMP_ID NUMBER(4) NOT NULL LAST_NAME VARCHAR2(30) NOT NULL FIRST_NAME VARCHAR2(30) DEPT_ID NUMBER(2) JOB_CAT VARCHARD2(30) SALARY NUMBER(8,2) Which statement shows the maximum salary paid in each job category of each department?（）A、SELECT dept_id, job_cat, MAX(salary) FROM employees WHERE salary MAX (salary);B、SELECT dept_id, job_cat, MAX(salary) FROM employees GROUP BY dept_id,job_cat;C、SELECT dept_id, job_cat, MAX(salary) FROM employees;D、SELECT dept_id, job_cat, MAX(salary) FROM employees GROUP BY dept_id;E、SELECT dept_id, job_cat, MAX(salary) FROM employees GROUP BY dept _ id job _ cat salary;
Examine the structure of the EMP_DEPT_VU view: Column Name Type Remarks EMPLOYEE_ID NUMBER From the EMPLOYEES table EMP_NAME VARCHAR2(30) From the EMPLOYEES table JOB_ID VARCHAR2(20) From the EMPLOYEES table SALARY NUMBER From the EMPLOYEES table DEPARTMENT_ID NUMBER From the DEPARTMENTS table DEPT_NAME VARCHAR2(30) From the DEPARTMENTS table Which SQL statement produces an error?（）A、SELECT * FROM emp_dept_vu;B、SELECT department_id, SUM(salary) FROM emp_dept_vu GROUP BY department _ id;C、SELECT department_id, job_id, AVG(salary) FROM emp_dept_vu GROUP BY department _ id, job_id;D、SELECT job_id, SUM(salary) FROM emp_dept_vu WHERE department_id IN (10,20) GROUP BY job_id HAVING SUM (salary) 20000E、None of the statements produce an error; all are valid.
限制从EMP表中只选出前5条记录的查语句为（）。A、SELECT TOP 5 * FROM EMPB、SELECT DISTINCT 5 * FROM EMPC、SELECT * FROM EMP WHERE ROWNUM6D、SELECT * FROM EMP WHERE ROWNUM=5
Which SQL statement would you use to remove a view called EMP_DEPT_VU from your schema?（）A、DROP emp_dept_uv;B、DELETE emp_dept_uv;C、REMOVE emp_dept_uv;D、DROP VIEW emp_dept_uv;E、DELETE VIEW emp_dept_uv;F、REMOVE VIEW emp_dept_uv;
Examine the structure of the EMP_DEPT_VU view: Column Name Type Remarks EMPLOYEE_ID NUMBER From the EMPLOYEES table EMP_NAME VARCHAR2(30) From the EMPLOYEES table JOB_ID VARCHAR2(20) From the EMPLOYEES table SALARY NUMBER From the EMPLOYEES table DEPARTMENT_ID NUMBER From the DEPARTMENTS table DEPT_NAME VARCHAR2(30) From the DEPARTMENTS table Which SQL statement produces an error?（）A、SELECT * FROM emp_dept_vu;B、SELECT department_id, SUM(salary) FROM emp_dept_vu GROUP BY department _ id;C、SELECT department_id, job_id, AVG(salary) FROM emp_dept_vu GROUP BY department _ id, job_id;D、SELECT job_id, SUM(salary) FROM emp_dept_vu WHERE department_id IN (10,20) GROUP BY job_id HAVING SUM (salary) 20000E、None of the statements produce an error; all are valid.
列出EMP表中，从事每个工种（JOB）的员工人数（）A、select job from emp;B、select job,count(*) from emp;C、select distinct job,count(*) from emp;D、select job,count(*) from emp group by job;E、select job,sum(empno) from emp group by job;
单选题You created a view called EMP_DEPT_VU that contains three columns from the EMPLOYEES and DEPARTMENTS tables: EMPLOYEE_ID, EMPLOYEE_NAME AND DEPARTMENT_NAME. The DEPARTMENT_ID column of the EMPLOYEES table is the foreign key to the primary key DEPARTMENT_ID column of the DEPARTMENTS table. You want to modify the view by adding a fourth column, MANAGER_ID of NUMBER data type from the EMPLOYEES tables. How can you accomplish this task?（）AALTER VIEW emp_dept_vu (ADD manager_id NUMBER);BMODIFY VIEW emp_dept_vu (ADD manager_id NUMBER);CALTER VIEW emp_dept_vu AS SELECT employee_id, employee_name, department_name, manager_id FROM employee e, departments d WHERE e.department_id = d.department_id;DMODIFY VIEW emp_dept_vu AS SELECT employee_id, employee_name, department_name, manager_id FROM employees e, departments d WHERE e.department_id = d.department_id;ECREATE OR REPLACE VIEW emp_dept_vu AS SELECT employee_id, employee_name, department_name, manager_id FROM employees e, departments d WHERE e.department_id = d.department_id;FYou must remove the existing view first, and then run the CREATE VIEW command with a new column list to modify a view.
单选题Which SQL statement would you use to remove a view called EMP_DEPT_VU from your schema?（）ADROP emp_dept_uv;BDELETE emp_dept_uv;CREMOVE emp_dept_uv;DDROP VIEW emp_dept_uv;EDELETE VIEW emp_dept_uv;FREMOVE VIEW emp_dept_uv;